dont show help page in web api - webapi

Question

I want to create help pages for ASP.NET Web API.
I created a new ASP.NET Web application project and select the Web API project template. It added Areas/HelpPage.
When I run the application, the home page contains a link to the API help page. From the home page, the relative path is /Help. It shows ValuesController action, but when I add another controller, the help page doesn't show that controller and any of its actions.
public class CalendarController : ApiController
{
private readonly string siteUrl = ConfigurationManager.AppSettings["SiteUrl"];
private readonly CalendarService calendarService;
public CalendarController()
{
calendarService = new CalendarService();
}
[HttpPost]
public async Task<ResponseModel<List<ApiCalendarViewModel>>> Paging(JObject param)
{
try
{
var startIndex = Convert.ToInt32(param["StartIndex"]);
var pageSize = Convert.ToInt32(param["PageSize"]);
var CalendarList = await calendarService.SelectAllAsync(startIndex, pageSize);
var list = CalendarList.Select(m => new ApiCalendarViewModel()
{
Author = m.Author,
Date = PersianDateTime.ToLongDateWithDayString(m.CreatedDate),
Excerpt = m.Excerpt,
Id = m.Id,
MainImage = siteUrl + m.Image,
Title = m.Title,
StartYear = m.StartYear,
EndYear = m.EndYear,
Semester = m.Semester.GetDisplayName()
}).ToList();
return new ResponseModel<List<ApiCalendarViewModel>>()
{
IsSuccess = true,
Data = list
};
}
catch (Exception e)
{
return new ResponseModel<List<ApiCalendarViewModel>>()
{
IsSuccess = false,
Message = e.Message
};
}
}
[HttpGet]
public async Task<ResponseModel<List<ApiCalendarViewModel>>> GetAll()
{
try
{
var CalendarList = await calendarService.SelectAllAsync();
var list = CalendarList.Select(m => new ApiCalendarViewModel()
{
Author = m.Author,
Date = PersianDateTime.ToLongDateWithDayString(m.CreatedDate),
Excerpt = m.Excerpt,
Id = m.Id,
MainImage = siteUrl + m.Image,
Title = m.Title,
StartYear = m.StartYear,
EndYear = m.EndYear,
Semester = m.Semester.GetDisplayName()
}).ToList();
return new ResponseModel<List<ApiCalendarViewModel>>()
{
IsSuccess = true,
Data = list
};
}
catch (Exception e)
{
return new ResponseModel<List<ApiCalendarViewModel>>()
{
IsSuccess = false,
Message = e.Message
};
}
}
}